package com.kaijie.utils;

import lombok.extern.slf4j.Slf4j;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

@Slf4j
public class HttpUtils {


    /**
     * 向指定URL发送GET方法的请求
     *
     * @param url   发送请求的URL
     * @param data 请求参数，请求参数应该是name1=value1&name2=value2的形式。
     * @return URL所代表远程资源的响应
     */
    public static String sendGet(String url, Map<String, String> data) {
        return get(url, data, new HashMap<>());
    }

    public static String get(String url, Map<String, String> data, Map<String, String> headers) {
        Set<Map.Entry<String, String>> entries = data.entrySet();
        StringBuilder dataSb = new StringBuilder();
        int i = 1;
        for (Map.Entry<String, String> entry : entries) {
            if (i != data.size()) dataSb.append(entry.getKey()).append("=").append(entry.getValue()).append("&");
            else dataSb.append(entry.getKey()).append("=").append(entry.getValue());
            i ++;
        }

        StringBuilder result = new StringBuilder();
        BufferedReader in = null;
        try {
            String urlName = url + "?" + dataSb.toString();
            URL realUrl = new URL(urlName);
            //打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            //设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            headers.forEach(conn::setRequestProperty);
            //建立实际的连接
            conn.connect();
            //获取所有响应头字段
            Map<String, List<String>> map = conn.getHeaderFields();
            //遍历所有的响应头字段
            for (String key : map.keySet()) {
                System.out.println(key + "--->" + map.get(key));
            }
            //定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch (Exception e) {
            //log.error("发送GET请求出现异常！", e);
        }
        //使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                //log.error("HTTP get error", ex);
            }
        }
        return result.toString();
    }

    /**
     * 向指定URL发送POST方法的请求
     * @param url 发送请求的URL
     * @param params 请求参数，请求参数应该是name1=value1&name2=value2的形式。
     * @return URL所代表远程资源的响应
     */
    public static String sendPost(String url, Map<String, Object> params)
    {
        return post(url, params, new HashMap<>());
    }

    public static String post(String url, Map<String, Object> params, Map<String, String> headers)
    {
        StringBuilder paramSb = new StringBuilder();
        params.forEach((name, value) -> {
            if (paramSb.length() > 0) {
                paramSb.append("&").append(name).append("=").append(value.toString());
            } else {
                paramSb.append(name).append("=").append(value.toString());
            }
        });
        PrintWriter out = null;
        BufferedReader in = null;
        StringBuilder result = new StringBuilder();
        try {
            URL realUrl = new URL(url);
            //打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            //设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            headers.forEach(conn::setRequestProperty);
            //发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            //获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            //发送请求参数
            out.print(paramSb.toString());
            //flush输出流的缓冲
            out.flush();
            //定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch(Exception e) {
           // log.error("发送POST请求出现异常", e);
        }//
        //使用finally块来关闭输出流、输入流
        finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
               // log.error("HTTP post error", ex);
            }
        }
        return result.toString();
    }

}
